Episodic cardiac symptoms, such as arrhythmia, are triggered by a wide variety of events including stress. In order for physicians to effectively diagnose the cause of the attack, they must analyze the particular pattern of the heartbeat irregularity. Electrocardiographic data is commonly used in such an analysis. Unfortunately, most arrhythmias are spontaneous and unpredictable, making detection nearly impossible while at the physician's office.
Portable electrocardiogram monitoring and recording devices for use by persons in outpatient environments have long been known. These devices include those which can be conveniently clipped on to a user's belt for wear throughout his daily routine. With the unit constantly in place, the user can simply press a button to start data recording whether it be periodic charting data or to signal the onset of an arrhythmia attack.
Typically, this type of portable unit is equipped with a sufficient amount of internal memory to record several minutes of ECG data. The unit can then be taken into the physician's office where inspection can be made of the electrocardiogram pattern recorded during the arrhythmia episode. Recent ECG recording devices have been equipped with wireless interfaces to relieve the user of the burden of traveling to the physician's office or physically connecting to a computer or phone line. Instead, the wireless interface permits the ECG data to be transmitted to the physician's office or to an analysis unit over a standard wireless network.
Clinical quality ECG/EKG data can have a bandwidth of 4 to 64 Kilo Bits per Sec depending upon the sampling rate. For continuous monitoring applications this implies tremendous memory and processing power requirements. Modern mobile platforms like smart phones and tablets are equipped with good processing power and gigabytes of memory that can be used to analyze and store ECG data.
However, in order to use this capability of a mobile device, an ECG acquisition device needs to send real time ECG data reliably to the mobile device. Older acquisition units may stream ECG data real time using wired interface like USB or Bluetooth Classic technology.
Bluetooth Low-Energy (BLE), which is a part of the Bluetooth 4.0 specification, is a more efficient wireless interface that can achieve the same data streaming performance with optimized battery life and ease of usage.
However, the currently published profiles over BLE don't support real-time streaming of ECG data. Some new ECG signal acquisition devices process the ECG signal locally to extract heart rate information and then send it over BLE interface using a heart rate profile.
By streaming raw real-time ECG data over BLE interface this invention allows a more compact implementation of ECG acquisition unit with longer battery life while providing the visibility into and flexibility of analysis of full raw ECG data on a mobile platform for continuous monitoring.
In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangement of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. In addition, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.